code segment
assume cs:code
start:
    mov ax,cs
    mov ds,ax
    mov dx,offset int_proc
    mov ax,2572h
    int 21h
    mov dx,21h
    in al,dx
    and al,0fbh
    out dx,al
    in  al,0a1h
    and al,0fbh
    out 0a1h,al
    mov dx,28bh
    mov al,0b8h
    out dx,al
    mov al,09h
    out dx,al
    mov bl,8
ll:    jmp ll
int_proc:
    mov dx,288h
    in al,dx
    mov dl,al
    mov ah,02h
    int 21h
    mov dl,0dh
    int 21h
    mov dl,0ah
    int 21h
    mov dx,20h
    mov al,20h
    out dx,al
    out 0a0h,al
    dec bl
    jnz next
    in al,21h
    or al,08h
    out 21h,al
    sti
    mov ah,4ch
    int 21h
next:    iret
    code ends
    end start
